INFLUENCE OF 2,4-D, IAA, AND DURATION OF CALLUS INDUCTION IN ANTHER CULTURES OF SPRING WHEAT

Culture media and environmental factors may significantly influence the yield of haploid plants from anther cultures. Our objectives were to identify a combination of 2,4-dichlorophenoxyacetic acid (2,4-D) and indoleacetic acid (IAA) concentrations which produce the maximum number of haploid plants, and to evaluate the effects of duration in induction medium on calli induction, plant regeneration, and green plant production from anther cultures in spring wheat. Significant (P less-than-or-equal-to 0.01) plant growth regulator concentration effects (2,4-D and IAA) were observed on the number of calli, green plants and albino plants produced, and on direct plant regeneration. Addition of 2,4-D to the induction medium resulted in significantly (P less-than-or-equal-to 0.01) higher means for all anther culture components compared to IAA. While addition of 2,4-D significantly (P less-than-or-equal-to 0.01) reduced plant regeneration, it substantially increased green plant percentage at a 0.3-mg 1-1 concentration of IAA. Use of response functions to estimate the maximum effective 2,4-D x IAA combination implied that higher 2,4-D levels in the induction medium should be investigated, and that the optimum hormone combination differs for plant regeneration and green plant percentage. Significant (P less-than-or-equal-to 0.01) effects of duration on callus induction medium were observed for plant regeneration and green plant percentage.